Regenerative cooling system



Sept. 17, 1940.

R. B. P. CRAWFORD REGENERATIVE COOLING SYSTEM 2 Sheets-Sheet 1 Original Filed Jan. 25, 1953 Se t. 17, 1940. R. a. P. CRAWFORD 2,214,880

REGENERATIVE coopmc SYSTEM Original Filed Jan. 25, 19s: 2 SheetST-Sheet 2 34 .96 9a as 0a Patented Sept. 17, 1940 REGENERATIVE COOLING SYSTEM Robert B. P. Crawford, New York, N. Y.

Original application January 25, 1933, Serial No. 653,362. Divided and this application March 15, 1937, Serial No. 131,088

4 Claims.

This invention relates to air conditioning systems and more particularly to air conditioning systems of the type which are regenerative in character.

In the ordinary type of air conditioning systems, or other systems, such as refrigerating, heating and ventilating systems, the dehumidification of the air has ordinarily been accomplished by chilling the air through the medium of refrigerating coils, cold water sprays, or the like, to condense out the moisture and increase the saturation of the air. However, such methods of dehumidification have numerous disadvantages, such as cooling the air to an extremely low temperature in order to remove the required amount of moisture, which necessitates increased heating or the air at a later stage of the conditioning process. I therefore contemplate the provision of suitable dehydrating means for performing this dehumidification, whereby the moisture contained in the air is absorbed by a suitable material, such as a chemical absorbent. Various chemical solutions, such as Prestone, ethylene-glycol, glycerine, soluble oils, or some of the hygroscopic salts, such as chlorides of lithium, calcium, or zinc, may be employed. Also, I contemplate the use of dry adsorbents, such as silica gel, green sand, lamisilite, and the like, wherein the incoming air is passed over the adsorbent and the moisture thereby removed onto the surface of the adsorbent.

It is a principal object of the present invention to provide an improved air conditioning system, the type utilizing a dehumidifying agent whereby operation of the dehumidifying agent is controlled in accordance with the humidity of the air which has been acted upon by the dehumidifying agent.

Another object of the present invention is to provide means responsive to the humidity of the air leaving the dehydrating chamber for controlling the operation of the concentrating means.

Other objects and advantages of the present invention will appear more fully from the following detailed description, which, taken in connection with the accompanying drawings, will disclose to those skilled in the art the particular construction and operation of a preferred form of my invention.

In the drawings:

Figure 1 is a diagrammatic sectional view of a simplified embodiment of my invention, wherein the water is removed from the absorbing. chamber by means of an electrolyzing cell;

Fig. 2 is a diagrammatic sectional view of a modified embodiment of the invention; and

Fig. 3 is a detailed sectional view of a modified form of concentrating means.

Referring now in more detail to Figure 1, I have disclosed in this diagram 9. simplified air conditioning system for supplying conditioned air to a room or other spacial chamber or compartment. This chamber is indicated generally by the reference numeral 5, and is provided with a pair of registers or grilles, the incoming register being indicated at 6, and the exhaust, or outlet register being indicated at I.

The fresh air inlet is indicated generally by the reference numeral 8, and is provided with a suitable damper, or closure means, such as the louvres 9, which may be either automatically or manually operated for controlling the quantity of fresh air admitted into the conditioning apparatus. The fresh air enters through the inlet 8, past the louvres 9, and thence directly into the dehydrating chamber, indicated generally at H]. If desired, suitable cooling coils, connected to the regenerative cooling system, can be disposed adjacent the louvres 9 for precooling the air stream, or may be placed in the solution for isothermally dehumidifying the air. Positioned at the inlet side of this chamber are a plurality of vertically extending pipes, indicated at l I, provided with suitable nozzles, or jets l2, which are adapted to spray the dehydrating solution into the air stream. It is to be understood that the number of spray nozzles, as well as the number of pipes, may be varied as desired, depending upon the capacity of the system, and the amount of dehydration that is desired. These pipes are so arranged that practically all of the air is intimately contacted by the dehydrating solution in order to provide efficient dehumidification thereof.

The chamber I0 is provided with a sump l3, which is adapted to collect the sprayed solution and the moisture collected from the air. Positioned at the outward side of the chamber I0 are a plurality of vertically extending baflles M which are adapted to remove any entrained particles of the conduit IS in a perfectly homogeneous mixture containing no particles of the dehydrating solution. The solution entrained by the baffles is returned to the sump l3. From the conduit Hi the air is led past a suitable damper l6 and is adapted to be mixed with the return air fromthe room 5 in the conditioning or mixing space indicated at IT.

The quantity of return air is controlled by means of a'damper l8, which damper may be automatically or manually controlled. I consolution from the air, so that the air passes into template, in the present invention, any suitable means for controlling the dampers, and the dampers may be so connected that opening movement of one will cause closing movement of the other. The quantity of fresh unconditioned air and the quantity of return room air is thus properly proportioned and mixed in the space H.

The mixture of fresh and return air is then passed over the coils 20, which coils are of appreciable length, and are provided with the extending radial fin members 2| for the purpose of providing an extended surface contact. As the air passes over these coils, it is progressively cooled, giving up its heat to the fluid circulating in the coils, and in this cooled, conditioned state, passes through the tapered portion 22 of the conditioning unit and into the blower 23. A suitable humidity sensing device, indicated at I6, is positioned in the path of the return air stream, and is adapted to regulate the quantity of fresh air being mixed with the return air by regulating the position of the damper I6. This is, however, only one manner in which this control may be effected, and I do not intend to limit the invention thereto. The blower 23 is of any suitable form, and is operated by means of an electric motor or other operating mechanism 24. The air is blown or forced through the delivery duct 25 and past the grille or register 6 into the room 5.

Referring now in moredetail to the cooling coils, indicated at 20, these coils have a suitable valve controlled inlet indicated at 28. A supply line 29 leads from a delivery pump 30 to the inlet 28. The delivery pump 30 draws Water from the sump 3| disposed adjacent the lower end of the cooling tower 32, and delivers water to the cooling coils 20.

This tower 32 comprises a vertically extending cylindrical shell which has its ends open, the lower end opening into the sump 3|. At the upper end, a suitable exhaust fan 33 is provided, this fan being actuated by the motor 34. The motor 34 is supported by means of suitable brackets 35 secured to the wall of the cooling tower shell 32. Suitable openings 36 are provided for permitting air to pass from the interior of the shell outwardly past the bracket members 35. Disposed immediately below the fan 33 is a suitable bafiie or eliminator member 31, this member serving to remove any entrained water particles from the air being exhausted from the tower.

The outlet of the refrigerating coil 20 is indicated at 38, and is connected by means of the pipe 39, controlled by the valve 40, to the laterally disposed spray nozzle 4| disposed within the interior of the cooling tower 32. The pipe 42 containing the spray nozzle 4| is connected at its end, by means of coupling 43, with a second pipe 44 which contains another set of spray nozzles. A suitable valve 45 is adapted to control the connection between these two sets of spray nozzles. The water from the nozzle 4| is discharged downwardly against the upwardly moving stream of air being withdrawn by the fan 33 from the tower, and is progressively cooled, approximating the wet bulb temperature of the air as it nears the lower end of the tower. In certain instances, as pointed out below, the wet bulb temperature of the air is substantially reduced before the air enters the tower, thus effecting a much greater cooling. This water is collected in the pump 3| and is delivered by the pump 30 back into the coil 20. These spray nozzles are so arranged that the pipe containing fluid at the higher temperature will discharge at the upper end of the tower, with the remaining pipe disposed below in accordance with the temperature existing therein. Thus a true countercurrent effect is produced. 5

A thermally sensitive member 46 is disposed in the sump, and is subject to the temperature of the water therein. This member 46 is adapted to control the speed of the motor 34 in accordance with the temperature of water in the sump, 10 for .controlling the quantity of air being exhausted from the tower, thus regulating the temperature of the water, within limits.

In the preferred embodiment of my invention, I also employ a series of precooling coils, these 15 coils being disposed in the path of the incoming air stream being supplied to the cooling tower. These coils are indicated generally by the numeral 41 and are positioned in the duct 48 which conducts the fresh incoming air to the 20 cooling tower 32. The coils 41 receive their supply of water from the pipe 49 which is connected at the T connection 50 with the pump 30. A suitable valve 5| controls the quantity of water sent through the coils 41. The other end of the 25 coils 41 leads, by means of pipe 52, to the spray nozzle pipe 44 disposed within the cooling tower. Connected to the first coil of the series of coils 41, as at 52, is a second pipe 53 which is adapted to enter the cooling tower 32 at a point below 30 the spray nozzle 4|, and is provided with a suitable nozzle for discharging water into the current of air passing upwardly through the tower. This pipe 53 conducts liquid at a cooler temperature than the liquid conducted by the pipe 52, inas- 35 much as it is positioned at the beginning of the series of coils 41.

The conduit 48 comprises an inlet indicated at 53, and a surrounding cylindrical portion extending about the cooling tower and indicated by the numeral 54. The cooling tower is provided with a series of openings struck inwardly from the surface, indicated at 55, through which the air is drawn upwardly by means of the fan 33. It therefore comes into intimate contact with the spray water being discharged downwardly, and the evaporation produced lowers the temperature of the water to a temperature approximating the wet bulb temperature of the air.

Considering now in more detail dehydration chamber l0, this chamber is provided, as pointed out, with a sump or discharge portion l3. A suitable discharge outlet 51 is provided for the purpose of withdrawing a portion of the solution from the sump. This discharge outlet 51 leads into an electrolyzing cell indicated at 58, this cell comprising the anode 59 and the cathode 60, these parts being well known and needing no further description. The cathode 60 is disposed within a porous cup 60', for a purpose to be here- '60 inafter disclosed. Suitable electrical connections, indicated at El, are led out from the two poles of the cell, and the energy controlling the cell is actuated by means of a suitable hydrometer switch, indicated in its entirety by the reference 65 numeral 62.

The switch 62 comprises an outlet 63 leading from the sump l3 to a suitable container 64 which is provided with an hydrometer float 65. The upper end of the hydrometer float has an 70 electrical contact member 66, which is adapted to make contact with a suitable contact member 61 positioned either above or below the cell, so that upon moving of the hydrometer 65 an electrical contact will be made to actuate-the cell 58. 7

Thus, as the water in the dehydrating solution increases, the specific gravity thereof decreases causing the hydrometer to sink and make contact, this contact energizing the cell 58 and thus producing electrolytic action in the cell. If a solution is used which has a specific gravity of a value less than that of water, wherein the addition of water serves to raise the specific gravity, the hydrometer switch can be so arranged, as illustrated, to make contact when the hydrometer rises. Ihis electrolyzes the water into its constituent components, namely, hydrogen and oxygen, which are discharged into the duct 68, which leads into the cooling tower 32. If desired, the respective constituents may be'collected in suitable containers instead of being transmitted to the tower.

As shown, there is also provided a suitable outlet'from the bottom of the sump I3, indicated at 69, which leads to the inlet side of a pump 10, the pump 10 having its outlet connected through pipe H to the pipe II and spray nozzle I2. This pump provides the necessary circulation for forcing the solution in spray form from the nozzle I2 into the dehydrating chamber I0.

It is therefore apparent that the control of the concentration of the dehydrating solution used in the air conditioning system is effected by the specific gravity of the solution, as determined by the hydrometer switch 62. Thus, the electrolytic cell is energized at such times as this concentration falls below that desired, and the water is thus removed to again bring the concentration back to the point desired. Thus an automatic control of the concentration of this solution is effected.

If desired, the concentration of the solution may be maintained in accordance with the humidity of the air stream after it leaves the baffies I4. A suitable humidity sensing device 62' is placed in the conduit I5, and is connected by suitable leads to a two-way switch 64' which intercepts the leads from the hydrometer switch 62. The operation of the cell is the same regardless of the control used, since the operator may optionally place the switch 64' in position to connect the hydrometer contacts 66, 61 to the cell 58, or may move the switch to its other position to connect the humidity sensing device 82' to the cell.

Referring now to the embodiment disclosed in Figure 2, is this embodiment I have provided an air conditioning and regenerative cooling system, in which the air used for the air conditioning system is drawn in to the same air inlet as that used in the cooling tower. In this system, the air inlet is designated by the reference numeral 85. The air passes through this inlet, and comes into contact with the coils 86, and from these coils The- . tion of the air from the air inlet 89 passes the connected to the inlet side of a pump 96.

room through suitable conduits. Cold water from'the sump 94 may be used to sensibly cool the return air in conduit 9|, or may be used directly in the unit coolers placed in the rooms, if desired, this water being then returned through the spray nozzles I02.

The cooling tower 90 is similar to that disclosed in Figure l, and comprises the lower sump portion 94, which is provided with an outlet 95 The pump 96 is adapted to force the water collected in the sump 94 through the coils 86 and 88, respectively, by means of pipes 91 and 98.

The return from the coils 86 is led through the return pipe 99 to a spray nozzle pipe I disposed in the upper portion of the cooling tower. The return'from the coils 88 is led through the pipe IM to a spray nozzle pipe I02 disposed in the cooling tower. The pipes I00 and I02 are provided with spray nozzles of the same type as disclosed in connection with Figure 1, and a connection may be made therebetween, if desired, as by means of the valved coupling I03. At the upper portion of the tower, a fan I04, corresponding to the fan 33 of Figure 1, is provided for exhausting air upwardly through the tower. The tower is provided adjacent the air inlet 89 with a plurality of openings I for allowing a portion of the air to enter the lower portion of the cooling towerto be drawn upwardly by the fan I04.

Disposed adjacent the upper end of the tower 90 is a cylindrical tank I01, and the air dischargedfrom the tower 90 is deflected out of the sides of the hood I08 and passes upwardly past the spray nozzles I09 carried by the pipe H0. The bottom of the tank I01 forms a sump, and a suitable outlet I II is provided therefor, leading from the sump to a pump II2 connected by means of the pipe I I3 to the pipe IIO carrying the spray nozzles I09. the fluid in the tank 93 is continuously withdrawn from the sump and discharged at the top of the tank. If desired, a portion of the water from the highly atomized spray nozzles in bank I00 may be entrained with the air and used to cool coil II5 without the use of the additional sump I01. This also, therefore, provides aregenerative cooling cycle.

The spray nozzles I09 are adapted to discharge directly upon a coil II5 located adjacent the top of the tank I01, the coil II5 containing the dehydrating solution coming from the solution tank H6. The solution in this tank H6 is at a relatively high temperature, due to the chemical reaction accompanying the formation of the dehydrating solution, and some means must be provided for cooling the solution before it is delivered to the dehydrating chamber 81.

I have therefore provided, leading from the outlet III of the tank, a suitable T connection whereby the solution is led over the coil I I5 and then downwardly through the pipe I I1 to the dehydration chamber II8, the dehydration chamber- I I8 being placed in the path of the fresh air.

stream leading to the cooling tower ,90. The dehydrator H8 is preferably of the film humidifying type, and comprises rotating disc members I I9 which have the lower periphery of their surfaces dipping into the dehydrating solution carried in the dehydrator I I8. From the dehydrator It is thus apparent that I I8, the solution is led back through the pipe I20 to the T connection IZI located adjacent the solution tank. A suitable pump may be provided to effect this circulation. This T connection I2I comprises, preferably, a swing check valve which permits the solution in the pipe I20 to enter the pipe I22 leading to the coil I I5, but does not permit solution leaving the tank II6 by means of the outlet pipe I23 to pass into the pipe I20. A valve I24 may be provided for replacing a portion of the solution in the tank I I8 with fresh solution from the makeup tank IIG when desired. In this manner, the dehydrating solution in the dehydrator H8 is maintained at a relatively cool temperature at all times by means of the regenerative cooling cycle associated with the tank I01. The dehydrator H8 is provided with a suitable outlet connection I25 which leads to suitable apparatus for removing the water from the dehydrating solution. It is thus possible to maintain the solution in the dehydrator II8 both cool and relatively concentrated at all times. In many cases coils 86 are not necessary.

A concentrating system for use in connection with the dehydrator H8 is shown in detail in Figure 3. In this figure, the outlet I25 from the dehydrator II8 leads to an electrolytic cell indicated generally at I30. The cell I30 is provided with an anode I3I and a cathode I32, preferably enclosed in suitable porous cups I33. The electrodes of the cell are connected in a suitable electrical circuit having the supply I34 and a switch I35.

This switch I35 may be a humidity responsive switch located in the air inlet 89 leading to the conduit SI and thence to the delivery duct. Upon an increase in humidity beyond that desired in the air entering the room, the switch I35, is adapted to be closed, completing a circuit between the electrodes I3] and I32, and thus tending to electrolyze the water out of the dehydrating solution. As this water is removed, the solution becomes concentrated, and. therefore is capable of absorbing more water from the incoming air. The humidity of the air thus decreasing, and after reaching a point lower than that desired, the humidity responsive switch I35 will open the circuit and thus allow the dehydrating solution to become diluted. Thus the concentration of the solution is maintained substantially constant and a constant humidity is present in the air entering the conduit 9| at all times.

In the operation of the electrolytic cell, oxygen is given off at the anode I3I, and is collected in the conduit I3'I. Hydrogen is given off at the cathode, and is collected in the conduit I38. The hydrogen is conducted through the relatively restricted portion of the conduit I38 to a nozzle I39, and is projected from the nozzle into a combustion space I40 provided by the enlarged portion of the conduit I3'I. Suitable baffles I4I are provided for preventing back firing of the flame into the hydrogen conduit I38.

I also preferably provide a burner I42, supplied with fuel through the conduit I43, for heating a plurality of tuyres or bafile members I44 and for thus applying heat to the tank I45. The tank I46 is adapted to receive a portion of the solution from the dehydrator I I8, and the heat from the burner I42 and the burning of the oxygen and hydrogen is adapted. to provide energy for evaporating any water which may be present in the solution in the tank I46. The incoming solution is led into the tank to the conduit I41 which passes into a plurality of coils I48 disposed in an interchanger I49.

The hot concentrated solution returning from the tank I46 is led through the conduit I50 into the interchanger and comes into contact with the coils I48. In this manner, the incoming solution is heated by the concentrated outgoing solution, and therefore less heat is necessary in order to effect evaporation of the water.

It is thus apparent, in this system, that both electrical and thermal means are utilized for removing the absorbed moisture from the dehydrating solution. In this manner, the dehydrating solution may be kept at a relatively high or constant concentration, and thus a relatively constant humidity may be imparted to the air.

It is to be understood that various modifications and rearrangements of the individual parts of .the air conditioning system disclosed in the accompanying drawings may be made without departing from the spirit of the invention.

I therefore do not intend to be limited to the exact embodiment of my invention disclosed in the drawings, but only in so far as defined by the scope and spirit of the appended claims.

This application is a division of my application Serial No. 653,362, filed January 25, 1933.

I claim:

1. In an air conditioning system having a return air duct and a fresh air duct, humidity control means for regulating the air drawn through one of said ducts, and means for tempering the admixture of air from said ducts before it passes ,into a delivery duct, the combination of a dehydrating chamber in said fresh air duct, means for intimately contacting the fresh air drawn through said duct with a dehydrating solution, and means responsive to the humidity of said fresh air leaving said chamber and prior to its admixture with said return air for maintaining said solution at a substantially constant concentration.

2. In an air conditioning system, a fresh air duct, a return air duct, means for dehumidifying the air in said fresh air duct, means for admixing said dehumidified air with the return air from said return air duct, means for tempering said admixed air, means for controlling the relative proportions of said air mixture, and means responsive to humidity of said dehumidified air stream prior to its mixture with said return air for controlling the dehumidifying means.

3. The method of conditioning air for an enclosure which comprises passing a stream of fresh air through a dehumidifying solution, sensing the humidity of said air as it leaves said solution, controlling the concentration of said solution'in accordance with said humidity sensing, subsequently mixing said air with return air, controlling the relative proportion of said mixture in accordance with the humidity of said return air, and tempering said mixture prior to its delivery to said enclosure.

4. The method of conditioning air for an enclosure, which comprises passing said air into a dehydrating chamber, spraying said air with a dehydrating solution to efiect absorption of moisture from said air independently of temperature differences between said air and solution, sensing the humidity of said dehydrated air stream, adiabatically controlling the concentration of said solution in accordance with said humidity sensing, mixing said air with return air from said enclosure, and tempering said mixture prior to its delivery to said enclosure.

ROBERT B. P. CRAWFORD. 

